For congestive heart failure, what is important is to have electrodes on the left side ideally in as many locations as possible but there is little room around the epicardial site to place the electrodes. The coronary sinus lead, and branches to some of the veins of the coronary sinus, could carry multiple electrodes on it. But, too many wires passing through the coronary sinus is problematic. So, local integrated circuits or satellite ICs, may be provided to drive the electrodes. The local integrated circuits, however, need power.
If additional wires are used to power the integrated circuits, it increases the number of overall wires going back to the device. As realized by the present inventor, it would be advantageous to use same two existing wires from the device that are used for pacing, to supply the power to the integrated circuits which are handling the electrode.
In this case, each satellite IC may have a capacitor to store the energy. A refresh pulse could be used to charge the capacitor to provide power to the electrode. The refresh is accomplished by delivering an electrical voltage pulse. A refresh pulse may be delivered right after a regular pacing pulse, so it lessens the impact on the sensing operation caused by opening sensing switches, which block sensing during that time. This approach has the disadvantage of requiring continuous pacing. The satellites may loose their configuration if pacing signals do not come at specified times.
For some patients, however, the pacing pulse may not be delivered or needed periodically. In this case, a standalone refresh pulse must be delivered to keep the satellites ICs alive. Although the refresh pulse is a short (e.g. tenths of micro-seconds) electrical pulse, this is enough to cause excessive disturbance and noise to the regular sensing operation. Therefore, the sensing switches must be opened to block all the noise.
As a result, the sensing operating is being disrupted, turned-off during and after the refresh pulse as well as its recovery, which can be tenths or hundreds of milliseconds. This sensing black-out period can be critical so should be avoided in some applications.
What is needed is to eliminate the need to open and block the sensing switches during and after the refresh pulse. Further, what is needed to allow the sensing system to run continuously—before, during, and after the refresh pulse. Moreover, what is needed is a way to reduce, or preferably eliminate, the sensing black-out period.